Sound-detecting apparatus



- March 4 192 1,485,538 w. L. WALKER SOUND DETECTING APPARATUS Filed Jan. 4, 1918 2 Sheets-Sheet 1 7 3 fi ve rzTi/arn' March 4 1924.

W. L. WALKER SOUND DETECTING APPARATUS 52 Sheets-Seat 2 Filed Jan. 4, 1918 Patented Mar. 4, 1924.

PATENT OFFICE.

unites STATES WILLIAM L. WALKER, or NEW YORK, N. Y., AssIeNoR TO WALKER SIGNAL AND EQUIPMEN'I: ooRroRA'rIoN, or 'NEW YOR -1v. Y., A CORPORATION or DELAWARE.

SOUND-DETECTING APPARATUS.

Application filed January 4, 1918. Serial No. 210,880.

To all whom it may concern:

Be it known that I, WILLIAM L. WALKER, a citizen ofthe United States, and resident of New York, in the county of New York and State of New York, have invented new.

and useful Improvements in Sound-Detecting Apparatus, of .whioh the following is a specification.

.This invention relates to sound detection and more particularly to the detection of sounds in water and to submarine signaling. While the present invention is adapted to a variety of uses it is particularly applicable in conjunction with the inventions disclosed in my prior applications Sr. No. 161,- l 179, filed April 11, 1917; Sr. No. 176,299, filed June 22, 1917; and Sr. No. 202,680, filed November 19, 1917. The aforesaid applications relate to im'proved apparatus for detecting sounds, especially under water, while the present invention is more particu-' I larly concerned with the conversion of the sound energy into electrical energy, or the control of electrical energy with the sound energy, and the treatment of the electrical energy. j

In detecting signals or sound'disturbances under water it is sometimes necessary to deal with signals or disturbances of extremely small intensity and at other times to receive signals or disturbances of comparatively large ma waves of minute intensity requires sensitive mechanism while the heavy disturbances necessitate means which will handle relatively large amounts of energy without damage. A universal system must possess delicacy to detect faint sounds and yet must have a suificiently wide range of adaptability to receive heavy impulses. Moreover, the system should be adapted to discriminate or distinguish between sounds of various characters and be adjustable to detect any one sound from a miscellany of sounds.

The principal object of the present invention is to attain the aforesaid results more perfectly than has heretofore been possible, viz, to attain great sensitivity, to be able to receive heavy signals, to distinguish between sounds of different characters, and to afford adjustment to receive a sound of a particular character.

In general the invention consists in receiving the sound emanating to the receivitude. The detection of sound ing station, converting the sound into electrical current variations, and then dilferem .tiating the component of current variation corresponding to the sound or signal to-be detected. Thus when a miscellany of sounds reach the receiving station as a composite sound, the composite sound is first converted into a variable electrical current of composite character and from this composite current the component corresponding to the signal or sound to be detected is selected ing instrument. The selection of the parand transmitted to an indicating or recordticular current component is preferably attained by the conjoint use of a unique vibrator hereinafter described and a microphonic cell arranged as disclosed in my said application Sr. No. 202,680, although it is to-be understood that in certain aspects of' the invention either the vibrator or the microphonic cell may be widely varied.

Moreover, the sound-responsive mechanism of the system may and preferably does assist in selecting the sound to be detected.

In the accompanying drawings,-

Figure 1 is a diagrammatic View of one embodiment of the invention;

Figure 2 is an end elevation of a cylindrical switch forming one element of Fig. 1;

Figure 3 is -a development of the cylindrical switch; I

Figures 4, 5, 6 and 7 show various circuit connections available with the cylindrical switch;

Figure 8 is a side elevation of the preferred embodiment of my improved Vibrator;

Figure '9 is a plan view of the vibrator;

Figure 10 is a transverse section on line 1010 of Fig. 8;

Figure 11 is a transverse section on line 11-11 of Fig. 8;

Figure 12 is a transverse section on line 1212 of Fig. 8; v

Figure 13 is a side elevation of a modified vibrator;

Figure 14 is an'elevation of one form of vibrator adjusting means;

Figure 15 is a transverse section on 15-15 of Fig. 14; and

Figure 16 is an elevation of a modified form of adjusting means.

The embodiment of my improved system shown in Fig. 1 comprises sound-responsive be detected, and. a receiver D forreprodvu vibratory electrical impulses,

C forselecting from mechanism A adapted to receive sound in, pulses and convert them into. electrical. im-

amplifying the:

.ing the component of sound.

has

of which carriesa rubber :the: diaphragm aperiodic.

The sound-responsive mechanism A is preferablyof the type application Sr. No. 202,680, which consists mounted on anoscillating arm '3 which is arrangedito be oscillatedbymeansof a diaw 'pliragm 4 theouter face of whichis exposed to the water or other medium through which the soundsare receivedand the inner face ring 4 to render Each microphonic cell is mounted on the lev'er arm through the i by dampmg means which may comprise a i :microphone arm is movedrelativelysiowly whereas when p the lever arm is rapidly oscillated; the rei tarded electrodeiis unable to follow the move- I ment and: relative motiontakes place between the two electrodesresulting in variations of current in the microphone circuits 6 and 7., These current variations are transmitted ithrough the switch ive rise to current variations ofincreased,

d sk i5 move together when the lever S to the audion B and O magnitude in the circuit of electromagnet C, the batteries 8 and 9 supplying potential to the input and output circuits of the audion respectively and the battery 10 serving to heat the filament ofthe audion to incandescence. The switch S is interposed in the circuit to effect various connections of the microphones with the audion B or electromagnet device C. The switch is rotary and has four sets of contacts 1111','12.12, 13-43 and l i-l i, the contacts 11, 12, 13 and 14 being .adapted to contact with the contacts 15, 16, 17 and 18 of the microphone circuits and the contacts 11', 12', 13' and 14' being adapted to contact with the contacts 19 and 20 of the audion input circuit. When the contacts 11 and 11 engage the respective sets of contacts 15-18 and 1920 as'shown in Figs. 1

and 2, the microphones 1 and 2 are connected in series with the audion as shown in Fig. 4; when the contacts 12 and 12' engage the sets of contacts1518 and 1920 the microphones are connected in parallel to the audion; and when in each of the other positions one of the microphones is singly connected to the audion. By this arrangement the microphones may be connected in series, parallel or individually to the audion depending upon the intensity of the sounds received. Moreover,

generallyshown atC in p Figs. Ste 12, comprises a disclosed in my prior taining a threaded rod 27' I fendso'f the bar. .The opposite e'nds of the Thus the two electrodes of g each bearing 31 is mounted {by means of screws 32 to support ithe centralportion of, the rod 27.

26 -are mounted i the audion may be cut out of thecircuit 1n gny suitable manneras by 1. l i e j The selecting and reproducing, apparatus Fig. 1 andsp'ecificab 1y illustrated in i band orstrip 22 mounted at spaced intervals between knife-edge supports 23 so as to vibrate to and fro. ports are is shown particularly in Fig. 11, the frame :T he knife-edge sup mounted on a calibrated circular I ofa pluralityv of microphonic cells 1 and 2 bar 24: so as to be adjusted therealong as if the sounds be of suflicient intensity closing switch i edprojection26 extending'upwardly into a groove 36 in the lower side of 2 rod 27 are threaded in opposite directions so. v medium of one. of its electrodes andthe other e i l i of its electrodes is free tomovewith the first electrode except as retarded byits inertia and in the other direction away the bar 27 with 'which'torotate theibar.

the bar conournaled in the bases 29 and at its middle by a base 30; A J

on the lease 30. init he groove 36 The threaded projections on the frames 25 by means of screws 33 so around rod 27; I are, d sposed in recessesm frame 25' so as as toiproject upwardly .into grooves 36 The knife-edge supports 2-3 to be reciprocated inwardly or outwardly by screws 34 to permit the insertion or removal of a band of any desired width. Plates 35 are fastened over the said recesses by means of screws 37:

The electromagnetic means the output circuit of the audion in Fig. 1 is mounted on the central frame 30 by means of a bracket 39 which is adjustable inwardly and outwardly by means of a screw 40 threaded through a lug 41 fastened to the side of frame 30 by a screw-42, the screw 42 cooperating with a slot in base 30 to hold the bracket in adjusted position.

On the side of the vibratory band opposite to the electromagnct is mounted a microphonic cell 44. The cell is mounted on the vibratory member through the medium of its diaphragm 45 and an airresisting, disk 46 is mounted on 38 disposed in If the moveaeeaese duced in the microphone circuit. However, when the vibrator vibrates relatively rapidly the body of the microphone, cannot follow the movement of, the diaphragm, especially when employing damping means such as illustrated by the disk 46, and the diaphragm is flexed back and forth giving rise to a variable current of the frequency of vibration of the vibrator. Instead of the disk 46 any suitable damping means may be employed as more fully set forth in my said-application Sr. No. 202,680.

The vibrator may be made to respond predominantly to any desired frequency of impulses by adjusting the supports 23 toward or from each other. For example, if

it is desired to select a signal of known frequency from a miscellany of sounds the vibrator is adjusted to the known frequencyand will respond predominantly to the component of the compound current wave in the audion circuit which represents the signal. This may be briefly explained as follows:

The miscellany of sounds striking the sound-responsive diaphragm 4;, including the. signal to be detected, is reproduced in the input circuit of the audion as a composite current wave corresponding to the,

composite sound wave more or less closely depending upon the character of the soundreceiving apparatus A. vThis'composite current wave is reproduced and amplified by the audion with substantially no change except in magnitude. The composite amplified wave thus transmitted to the vibratoris diflerentiated by the vibrator, when the vibratory member is adjusted tothe frequency of the component signal, so that the signal is alone transmitted to the receiver D. When the signal ceases the vibrator ceases to vibrate to any appreciable extent.

Supplementary or alternative methods of adjusting the vibrator are shown in Figs. 13 to 16. Fig. 13 shows weights 47 adjustably mounted on a vibratory member 48. These weights are U-shaped as shown in Fig. 14 and their inner edges are relatively narrow as shown in Fig. 15 so that when clamped to the vibrator by the thumbscrews 49 they engage a relatively narrow area of the vibrator. In order to supplement the inertia of the weights the air resistance of disks 50 mounted on the weight may be utilized as illustrated in Fig. 16.

In supplementing the device shown in Fig. 9, for example, shown in Figs. 13 to 16, the vibration of the band 32 maybe varied by shifting the weights toward or from the center of the band, the weights preferably being maintained equidistant from the magnet 28 at the center.

I claim a 1. n pp at s f r d e t ng ounds of a with weights such as" associated with said'conductors whereby additional energy is given the electrical means for operating the vibratory member of the sound selecting device. 1

2. In apparatus of the character described, the combination of an elongate vibratory member, sound-responsive means for vibrating. said member, movable supports engaging the elongate member at spaced intervals whereby said member may be tuned to a 'certain frequency so as to constitute a barrier to trains of impulses of other frequencies, and means for conjointly moving the supports to and from each other.

' 3. In apparatus of the character described,

the combination of an .elongate vibratorymember, electromagnetic means for vibrating said member, current-varying means arranged to be actuated by said member, movable supports engaging the elongate member at spaced intervals whereby said membermay be tuned to a certain frequency so as to constitute a barrier to trains of impulses of other frequencies, and means for conjointly moving the supports to and from each other.

4. the combination of a. flexible band knife-edge means for supporting the band at spaced intervals so that the portion of the band therebetween may vibrate to and fro, means for conjointly moving the knife-edge means to and from each other, and current-varyi means arranged to be vibrated by said ban the band being tunedv to vibrate predominantly at a relatively high frequency.

5. In apparatus of the character described, the combination of a flexible band, supports engaging the band at spaced intervals so that the portion of theband therebetween may vibrate to and fro, and means for conjointly moving the supports to and from eachother. F

6. In apparatus of the character described, the combination of a flexible band, supports engaging the band at spaced intervals so that the portion of the band therebetween may vibrateto and iro, means for conjointly moving the su ports to and from each other, means for vi In apparatusof the character described, I

rating the band, and means associated with the band intermediate the upports for affecting the frequency of vibrationof the band. 7. "In apparatus of the character described, 5 the combination of a flexible band, supports engaging the band at spaced intervals so that the portion of the band therebetween may vibrate to and fro, means for conjointly a moving the supports to and from each other, 1 and means adjustably mounted on the band intermediate the supports for regulating the vibration of the band. e 8. In apparatus of the character described, the combination of a flexible band, supports 1 engaging the band at spaced intervals. so that the portion of the band therebetween may vibrate to and fro, means for conjointly moving the supports to and from each other, and air-resistors adjustably mounted on the 2 band intermediate the supports for regulating the vibration of the band.

9. In apparatus of the character described, the combination of a flexible band, supports engaging the band at spaced intervals so 2 that the portion of the band therebetween may vibrate to and fro, means supported at a midpoint between said supports for vibrating the band, and means for conjointly moving the supports to and from each other and maintaining said means in the same position relative to the supports. I

10. In apparatus of the character described, the combination of a base member, supports adjustable thereon, a flexible band engaged in said supports, means mounted on the base at a midpoint between said supports for vibrating the band, and,an adjusting rod having means engaging said supports whereby a movement of the rod in one direction moves said' supports toward each other and a movement of the rod in the other direction moves said supports away from each other.

11. Inapparatus of the character described, the combination of a flexible band, supports engaging the band at spaced intervals so that the portion of the band there- -between may vibrate to and fro, electrical means for vibrating the band, means for adjusting the correct distance between the vibrating means and the vibrating band and means associated with the band intermediate the supports for affecting the frequency of vibration of the band.

Si ned by me at Boston, Mass, this th day of December, 1917.

WILLIAM L. WALKER. 

